James Dupré Lance was born at Boulogne, France, probably on 28 January 1829. He was the son of Madelina Louisa Porcher and her husband, John Edwin Lance, an Anglican clergyman. Little is known of James's early life. He attended the Royal Indian Military College, Addiscombe, and in 1848 was posted as ensign in the East India Company army, rising to lieutenant in 1855. In 1856 Lance arrived in New Zealand on leave, visiting J. W. Mallock and his brothers at Heathstock, North Canterbury. He went back to strife-ridden India in 1857, and was attached as an interpreter to the 42nd (The Royal Highland) Regiment of Foot; he was present at the relief of Lucknow.
Lance returned to New Zealand in 1860 and bought the licence of the Fourpeaks run, disposing of it soon after. He went to England in 1861 or 1862, and while there married Mary Ann Eliza Mallock at Tormohan, Devonshire, on 20 February 1862. The couple sailed for Lyttelton, New Zealand, probably in 1862; they were to have four children. In complex negotiations the Mallock brothers sold Horsley Down to Lance, retaining the adjacent Heathstock. The two runs were managed as one, under a partnership between the Mallocks and Lance. Lance built a homestead at Heathstock and ran the estate like an English country squire, turning it into one of the most hospitable houses in New Zealand. Lady Barker was so enchanted with her visit in 1865 that she drew an idyllic picture in Station life in New Zealand; William Pember Reeves commemorated it in verse. Lance had a wide reputation as a genial host, and the celebrated racehorses Traducer, Blood Royal and Anteros all stood at the Heathstock and Horsley Down stud.
Lance entered the Canterbury Provincial Council in 1865 in succession to his brother, Henry Porcher Lance. He was persuaded to contest the superintendency against William Sefton Moorhouse in 1866. He stood as the candidate of the runholders, styling himself an 'independent conservative' of liberal views. Members of the government party helped with his considerable election expenses, and J. E. FitzGerald acted as his agent. His programme was too much in defence of his fellow runholders, but Lance attracted support with his courage, fearlessness and courtesy. Nevertheless, he finished a distant second to Moorhouse. In 1865 he was appointed to the Legislative Council, serving until 1867 when, following a buggy accident, he resigned in order to visit England for medical treatment. He remained there and in France until 1879, studying agriculture.
Following his return to New Zealand, Lance resumed his role of a local man of substance, becoming prominent in business, politics and sport. He was elected to the House of Representatives as member for Cheviot in 1884, largely as a supporter of Julius Vogel. Following the defeat of the Stout–Vogel government in 1887, the opposition was left leaderless when Vogel returned to England. Lance was elected a chairman of a leadership committee on 7 August 1888 as part of an attempt to unite Vogelites, liberals and the radical followers of Robert Stout and John Ballance. He surrendered his role when John Ballance became leader of the opposition in 1889. Lance was opposed to Ballance's land and taxation policies and played no further part in colonial politics following his defeat in 1890.
Lance could have made a fortune out of Horsley Down–Heathstock, which consisted of about 120,000 acres of leasehold and freehold land; the highest sheep return was 74,061 in 1885. Instead, by the early 1890s he was heavily over-committed. He had spent lavishly on improvements and on measures to combat the increasing rabbit menace, had bought out his partners, and in 1892 purchased more than 88,000 acres of New Zealand Midland Railway Company land on his run. By 1896 Lance was virtually bankrupt. Sale of stock and land provided meagre returns, and in 1896 and 1897 the government bought nearly 4,000 acres for settlement.
Lance died at Waiau, North Canterbury, on 28 March 1897. Mary Lance, who died in 1923, retained a house on Horsley Down and several hundred acres of the land.